Question

我在一家律师事务所工作，该案件管理系统将接口链接到SQL数据库。我在SSRS中编写查询来运行报告。我正在尝试运行案例信息报告。一些信息正好在“案例”表（或vcases视图）中，但我也试图链接来自“requirements_offers”表的信息。每个案例都有多个需求和优惠，因此我在联接中使用MAX函数来仅提取每个案例的最新需求记录。不幸的是，这样做可以消除没有要求的情况。我需要出现所有案例。

我尝试使用嵌套在MAX函数中的CASE语句将NULLS或空字段转换为随机的早期日期，但我仍然无法将所有案例都显示在报告中。

有什么想法吗？我是SQL的相对新手，没有正式的培训。任何帮助将不胜感激。你可以看到下面的代码。（P.S.我认为我没有权利创建临时表。）

SELECT vc.case_number AS "Matter ID", vc.style, vc.atty2_name AS "Handling Attorney", m.max_demands_date, do.demands, do.demands_notes, sa.authorized,      
(SELECT TOP 1 vl.computename        
FROM vcases vca     
LEFT OUTER JOIN case_parties cp     
ON vca.case_sk = cp.case_sk     
JOIN case_parties cpp       
ON cp.parent_sk = cpp.case_parties_sk       
JOIN vlegal_entity vl       
ON vl.legal_entity_sk = cp.entity_sk        
JOIN vlegal_entity vlp      
ON vlp.legal_entity_sk = cpp.entity_sk      
WHERE (vca.case_sk = vc.case_sk) AND (cpp.role_sk = '3557') AND (cp.role_sk = '3986') ) AS "Plaintiff//'s Attorney",        
(SELECT cp.reference_number     
    FROM cases AS ca    
        LEFT OUTER JOIN case_parties AS cp
        ON ca.case_sk = cp.case_sk
    WHERE (cp.role_sk = '3706')     
        AND (ca.case_sk = vc.case_sk)) AS "Claim Number"


FROM        
vcases vc       
LEFT OUTER JOIN     
case_parties cp ON vc.case_sk = cp.case_sk      
LEFT OUTER JOIN     
vlegal_entity vl ON cp.entity_sk = vl.legal_entity_sk       
LEFT OUTER JOIN     
settle_authority sa ON vc.case_sk = sa.case_sk      
LEFT OUTER JOIN         
demands_offers do ON vc.case_sk = do.case_sk        

INNER JOIN      
 (SELECT DISTINCT max(
(CASE WHEN do.demands_date = '' THEN '1/1/1900 00:00:00'
             ELSE do.demands_date
              END)
  ) as "max_demands_date", vc.case_sk       
   FROM vcases AS vc        
   JOIN demands_offers AS do ON vc.case_sk = do.case_sk     
   GROUP BY vc.case_sk) AS m        
  ON vc.case_sk = m.case_sk  AND        
  do.demands_date = m.max_demands_date      

WHERE (vc.closed_ind = 'O') AND (cp.role_sk = '3816') AND (vl.client_number = 'EAS-01') AND (vc.lawtype_code <> 'FA')       
ORDER BY vc.case_number

Answer 1

你的查询可能写得更紧凑，性能更好，但是要启动你，这就是删除行没有要求的部分：

INNER JOIN      
 (SELECT DISTINCT max(
(CASE WHEN do.demands_date = '' THEN '1/1/1900 00:00:00'
             ELSE do.demands_date
              END)
  ) as "max_demands_date", vc.case_sk       
   FROM vcases AS vc        
   JOIN demands_offers AS do ON vc.case_sk = do.case_sk     
   GROUP BY vc.case_sk) AS m        
  ON vc.case_sk = m.case_sk  AND        
  do.demands_date = m.max_demands_date

需要

LEFT JOIN      
 (SELECT DISTINCT max(
(CASE WHEN do.demands_date = '' THEN '1/1/1900 00:00:00'
             ELSE do.demands_date
              END)
  ) as "max_demands_date", vc.case_sk       
   FROM vcases AS vc        
   JOIN demands_offers AS do ON vc.case_sk = do.case_sk     
   GROUP BY vc.case_sk) AS m        
  ON vc.case_sk = m.case_sk  AND        
  do.demands_date = m.max_demands_date

原因是(A INNER JOIN B)仅在可以将A中的行与B中的行匹配时保留记录。当没有需求时，派生表（子查询）为max_demands_date返回NULL ，do.demands_date = m.max_demands_date无法匹配。这会导致case记录被删除。

Microsoft SQL MAX（）不包括具有NULL的行

1 个答案: